Stupid question but is it safe to go below the minimum published charge? If so is there a rule of thumb you should follow?

depends on the powder being used...

slower powders? Not really...

faster powders? No problem...

There are some powders you can and there are others you can't go below mim with.

H110 is well known for not going below min.

quote:

Originally posted by p dog shooter:
There are some powders you can and there are others you can't go below mim with.

H110 is well known for not going below min.

Hodgdon warns against going below their min with H100 due to its tendancy to burn very eradic at less then optimum pressure and can cause bullets to be stuck in the barrel where a second shot could be dangerous.
Fast or slow, both can be trouble at low charges but not always due to spikes.

below minimum can be bad -- lets say that, no, you should neither exceed or go under recommended loads without serious risk of harm.

with slow powders, YES, there is serious risk of kaboom

not meant as a slander to the OP...

if you have to ask, I think one would be missing the experience to venture off the beaten path...

First of all, most sources don't list a "minimum" load, rather, they list a "starting load". There is a difference in the two and they are not necessarily the same.

Perhaps it would have been helpful to predicate your question on what it is you wish to accomplish. I am going to assume that you had a practical goal in mind (which would be some kind of reduced load), rather than just asking an academic question.

However, "academically", there are some powders which exhibit erratic (though not necessarily dangerous) behavior when loaded to low densities, while there are other powders which have been illustrated to be subject to dangerous pressure excursions when loaded to low densities (known as "Secondary Explosion Effect" or SEE, the theoretical physics of which I won't go into.)

If your goal is indeed reduced loads, then there are a limited number of powders which have proven to be particularly well adapted to this use like IMR/H4895 and SR 4759 and a few others. Instead of just artibtrarily reducing the charge of whatever powder you have on hand, refer to specific recipes for reduced loads with proven powders for the best results.

quote:

Originally posted by p dog shooter:
There are some powders you can and there are others you can't go below mim with.

H110 is well known for not going below min.

I have first hand experience sticking bullets in a .357 revolver barrel using H110.
The same loads, however, work just great in a .357 rifle. roger

Bad idea with "magnums".

Do not go below the
"minimum published" charge, is a good rule to follow. Google "Hodgdon Youth Loads" for the exception to this rule.

quote:

Originally posted by seafire/B17G:
not meant as a slander to the OP...

if you have to ask, I think one would be missing the experience to venture off the beaten path...

+1